leetcode 605. Can Place Flowers

Suppose you have a long flowerbed in which some of the plots are planted and some are not. However, flowers cannot be planted in adjacent plots - they would compete for water and both would die.

Given a flowerbed (represented as an array containing 0 and 1, where 0 means empty and 1 means not empty), and a number n, return if n new flowers can be planted in it without violating the no-adjacent-flowers rule.

Example 1:

Input: flowerbed = [1,0,0,0,1], n = 1
Output: True

Example 2:

Input: flowerbed = [1,0,0,0,1], n = 2
Output: False

Note:

1. The input array won't violate no-adjacent-flowers rule.
2. The input array size is in the range of [1, 20000].
3. n is a non-negative integer which won't exceed the input array size.

贪心，从前往后遍历同时判断两边是否满足空的要求

public class Solution {
    public boolean canPlaceFlowers(int[] flowerbed, int n) {
        int cnt = 0;
        for(int i=0; i<flowerbed.length && cnt<n; i++){
            int pre = (i==0) ? 0 : flowerbed[i-1];
            int next = (i==flowerbed.length-1) ? 0 : flowerbed[i+1];
            if(pre==0 && next==0 && flowerbed[i]==0){
                cnt++;
                flowerbed[i] = 1;
            }
        }
        return cnt==n;
    }
}